Paul Annacone, the former coach of Roger Federer and Pete Sampras, is now coaching Sloane Stephens on a trial basis, TENNIS.com has learned.

Annacone recently split with Federer and stated at the time he had not decided what he would do in the future. But the American has been working with Stephens for a few hours a day in Los Angeles, where they both reside.

Annacone coached Federer to his last Grand Slam title at Wimbledon in 2012, coached Sampras to numerous Grand Slam titles, and headed player development at both the USTA and LTA. He also coached Tim Henman for a stint, but has never overseen a top women’s player as private coach.

The two will work together at least until Stephens leaves for the Australian Open toward the end of December to compete in the Hopman Cup. She will play Sydney the following week and then head to Melbourne to try and defend semifinal points from the 2013 tournament.

This year, Stephens worked with USTA coach David Nainkin, who coached her to the second week of every Grand Slam and to a Top 15 ranking.

“We were happy to work with and support Sloane for the time that we did and would be happy to support her in the future as well,” said USTA Player Development chief Patrick McEnroe.

Stephens is currently ranked No. 12 and is the youngest player in the Top 30. Sources say that while Stephens enjoyed working with Nainkin, she did not want to ask the USTA to allow him to exclusively coach her, as he also works with fellow American Sam Querrey. But another source said Stephens never contacted the USTA to ask about it; regardless, that is not how USTA Player Development works, as their coaches work with multiple players.